eBay adjustable CC/CV module for 4.3v cell charging?

OK, I think I have it figured out. The middle pot does nothing but set the point (based on current) when the 'charge' LED turns off and lights the 'OK' LED. The board does not shut off when finished, but when the cell voltage is equal to the regulator output voltage, no current will flow.

Set the open circuit voltage to 4.20v, 4.30v, 4.35v, whatever.

Short the outputs with an ammeter, adjust the current pot to the desired 'end current', or the amperage where you want the LEDs to indicate charge complete - say .1A. Then adjust the middle pot until the middle 'CH' LED just turns off. During the charge when current to the cell falls below that point the LEDs will change.

Short outputs again with the ammeter, set the max charge current, say 1A.

At the start of a charge cycle with a flat cell, current will be limited to 1A (the cell would take more than that, if it weren't limited). The far right LED (marked 'CC/CV') will be on, and the middle 'CH' led will be on. The 'OK' LED will be off. In this pic the 'CC/CV' LED is red and on dimly, the blue 'CH' LED overwhelms the camera:

In the middle part of the charge the current into the cell will fall under the 1A limit, the 'CC/CV' LED will turn off, middle 'CH' LED stays on.

Near the very end both 'CH' and 'OK' will be lit together:

When the charge current falls below the set point and cell voltage has risen to the voltage set point, the 'CH' LED will turn off, with only the 'OK' LED on:

The cell isn't completely finished at that point, but, since output voltage can never go over your setting, if you set it to the correct voltage it should be ok to let it run like that basically forever, I suppose. For a 4.30v setting if you remove the cell as soon as the 'CH' light turns off, cell's resting voltage will be around 4.26-4.27v. Another 15-20 minutes will bring it up to 4.29-4.30v.

Thanks comfy! I'm really tempted to try and adapt this module into a cheap charger, but I know it would be forever before I'd get around to it with so many mods sitting and waiting.

-Garry

My idea would only work for a single bay charger, right? What would happen if you charged two in parallel but the batteries had different voltages? Would it still work for that?

-Garry

If you put two batteries in a parallel box current will flow from the higher voltage one to the lower, whether you are charging them or not.

This board would do multiples in parallel, just crank up the amperage. But they all have to be fairly close to the same voltage at the start. I always charge LiIons in parallel or as singles, I don't have the patience to sort through everything needed to mess with balance leads and adapters and whatnot to do series charging.

Yeah I didn't even think about the higher voltage cell charging the lower voltage cell (by itself w/o charger even connected). Guess that's not a real good situation. Better stick to a single cradle charger then. Problem is, I don't know if the cheap chargers have enough room inside for the module. Here's the single bay one I was looking at for a "host".

-Garry

The thru-holes (if they are that) on the far right that appear to be labled B1, B2, B3, ?. Are they for balance charging cells in series?

No, this thing doesn't even shut off when finished. My board has the same components in the same locations but the PCB is different, mine has no holes outboard of the indicator LEDs. There's not enough parts on there to do anything like balance charging.

Oh, so they are for remote indicator LED's?

I have no idea, I don't have one with those holes. But a board with a single LM2596 chip and a few indicator LEDs isn't capable of doing balance charging.

Awesome thread! I really appreciate all the work you guys put your posts.

After playing for a few more hours I think a better way of adjusting the CH to OK transition point is to just ignore the CH adjustment and monitor the cell voltage, when it's finished and voltage has reached your set point then adjust the CH pot.

At any point during the charge you can mess with the CH (middle) pot without affecting anything other than which LEDs are on. Starting from fully CCW, turn the CH pot clockwise until the CH light turns off, then a little back CCW will turn on both CH & OK at the same time. As more charge goes into the cell the voltage rises and the current decreases, and gradually the CH light dims and the OK light brightens. Turn the CH pot a little further CCW and you'll get both CH & OK lights again. Keep chasing it like that and at the end of the charge you'll have a feel for the setting that'll be closer to accurate for indicating the charge is actually complete.

They are so proffesional. :heart_eyes:

I just got mine. They look good on the surface. Now to decide what to use them for.

those look perfect for driving a couple of these for some diy cabinet / shelf lighting

speaking of these lights has anyone seen anywhere other than dx that sells them?

There are better choices if it's gonna be used as a LED driver, you don't need the charging capability (though the plain ones can do charging as well, just have to be adjusted right).

I had one of the ~$11 boost models, it successfully ran a 100w array at 31v/3.5A from a 16v input.

Looks like this is going to be added to my collection.

Seems like the most appropriate method for a good 4.3V charger.
Not sure if I should get two, another being for 4.35V.

Powered via re-purposed computer PSU.
Not sure what I'm going to use for battery host yet.

Thanks for the research boys.

In post #20 above - Here's the single bay one I was looking at for a "host". (US Plug version) May not be enough room for this board though.

-Garry

If you're planning to hide the board away inside the ex-charger case, I have to warn you these are not set-and-forget type devices, you'll want to check and adjust at least the voltage each time you use it. The current setting seems to stay reasonably on target but the voltage adjustment is awful touchy.

And there's no problem with charging multiple cells at a time, given they're the same make/model and their starting voltages are within a range of .04-.06v.

Well that stinks!

-Garry

that doesn’t seem to be a true cc/cv charger. i.e. should STOP charging once the current drops to around 10% of initial current. so if you leave that overnight it will trickle charge which actually hurts the cell